feat: 보고서(Reports) API 구현

- 일일 일보 조회/엑셀 다운로드 API 추가
- 지출 예상 내역서 조회/엑셀 다운로드 API 추가
- ReportService: 전일/당일 잔액 계산, 월별 지출 예상 집계
- Laravel Excel을 이용한 엑셀 내보내기 구현
- Swagger 문서 작성 완료

app/Http/Controllers/Api/V1/ReportController.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace App\Http\Controllers\Api\V1;
+
+use App\Exports\DailyReportExport;
+use App\Exports\ExpenseEstimateExport;
+use App\Http\Controllers\Controller;
+use App\Http\Requests\V1\Report\DailyReportRequest;
+use App\Http\Requests\V1\Report\ExpenseEstimateRequest;
+use App\Http\Responses\ApiResponse;
+use App\Services\ReportService;
+use Maatwebsite\Excel\Facades\Excel;
+
+class ReportController extends Controller
+{
+    public function __construct(
+        private readonly ReportService $service
+    ) {}
+
+    /**
+     * 일일 일보 조회
+     */
+    public function daily(DailyReportRequest $request)
+    {
+        $report = $this->service->dailyReport($request->validated());
+
+        return ApiResponse::handle(__('message.fetched'), $report);
+    }
+
+    /**
+     * 일일 일보 엑셀 다운로드
+     */
+    public function dailyExport(DailyReportRequest $request)
+    {
+        $report = $this->service->dailyReport($request->validated());
+        $filename = 'daily_report_'.$report['date'].'.xlsx';
+
+        return Excel::download(new DailyReportExport($report), $filename);
+    }
+
+    /**
+     * 지출 예상 내역서 조회
+     */
+    public function expenseEstimate(ExpenseEstimateRequest $request)
+    {
+        $report = $this->service->expenseEstimate($request->validated());
+
+        return ApiResponse::handle(__('message.fetched'), $report);
+    }
+
+    /**
+     * 지출 예상 내역서 엑셀 다운로드
+     */
+    public function expenseEstimateExport(ExpenseEstimateRequest $request)
+    {
+        $report = $this->service->expenseEstimate($request->validated());
+        $filename = 'expense_estimate_'.$report['year_month'].'.xlsx';
+
+        return Excel::download(new ExpenseEstimateExport($report), $filename);
+    }
+}